The present invention pertains to thermoelectric modules and to a heating and cooling apparatus for controlling the temperature of an object, either an inanimate object or an animate object, such as a human body. By way of example, with reference to application of the heating and cooling apparatus to an object such as a human body, the apparatus might be used to treat injuries or might be incorporated into clothing, including being used as a thermal control garment in protective clothing. Likewise, the apparatus might be used for signature profile modification or to provide thermal masking to camouflage personal, material, or equipment.
There are frequent needs for portable heating or cooling devices. By way of example, muscle and tissue injuries might be treated by heating, cooling, massaging, and electrically stimulating the injured area. A heating or cooling apparatus might be incorporated into a protective wrap to be positioned around the injured body part to heat or cool the injured body part, as desired. Likewise, a heating or cooling apparatus might be incorporated into protective clothing to enable a person to enter an area of extreme temperature, for example a fire fighter going into a building that is on fire. A person who has suffered from extensive burns to the body must be kept warm, for example beneath a blanket or other covering which provides heat. Another application of a portable heating and cooling apparatus is a portable cooler, for example for holding temperature-sensitive material, such as blood during transportation, or such as a picnic cooler. Further, temperature variations can be utilized to provide signature profile modification, thermal masking, or camouflage. While thermoelectric modules such as Peltier devices can be conveniently incorporated into various types of heating and cooling apparatus, known thermoelectric modules permit undesirable heat transfer from their heat releasing substrate panel, through the module interior, to their heat absorbing substrate panel. This significantly reduces the efficiency of the thermoelectric module.
In the past, injuries requiring cold compresses have often been treated by a cloth or bandage that has been cooled in a freezer and applied to the injured area. Ice packs have also been used to apply cooling therapy to a body surface. Injuries requiring heat treatment have often treated by a cloth or bandage that has been heated in, for example, a microwave oven, and then applied to the injured area. Similarly, heating pads and chemical salts have been applied to an injured area that requires heat therapy U.S. Pat. No. 5,800,490, the disclosure of which is incorporated herein by reference, discusses various heating and cooling devices that have been used in the past for therapeutic purposes.
These different apparatuses have various shortcomings. Ice packs and heated cloths, for example, return to ambient temperature in a relatively short time. Other apparatuses likewise have drawbacks, such as requiring a non-portable energy source or such as being capable of inadvertent or improper operation if not being worn properly.
The present invention is a heating and cooling apparatus adapted to be applied to an object to control the temperature of the object, whether the object be an inanimate object or an animate object such as a person. A heating and cooling apparatus in accordance with a preferred embodiment of the invention includes a plurality of thermoelectric modules adapted to contact the object in a pattern, and a power source enabling each thermoelectric module to create a temperature difference module so as to control the temperature of the object in accordance with the pattern.
Each thermoelectric module includes a plurality of semiconductor pellets positioned between first and second thermal conduction layers or substrate panels. The plurality of thermoelectric modules can be positioned with their substrate panels defining substantially continuous surfaces. Alternatively, the plurality of thermoelectric modules can be positioned such that a substantially continuous surface is defined by the first substrate panels of some of the thermoelectric modules and the second substrate panels of others of the thermoelectric modules. If desired, a twisted portion can join the two portions of the continuous surface.
The heating and cooling apparatus can further include an electrical stimulating device to apply an electrical stimulus to the body and/or a pressure device to apply pressure to the body. Further, temperature sensors can be incorporated to permit monitoring of the temperature of the various thermoelectric modules as well as pressure sensors to monitor applied pressure.
The power source can include a voltage supply for supplying the voltage and a controller for controlling and/or monitoring the supplied voltage and associated current. The controller might be a read only memory or a field programmable gate array. Alternatively the controller might comprise a processor and a memory for storing a program for the processor, or a set of processors and associated memories. Alternatively, the voltage source further can include one or more input units connected to the controller to receive input signals and to apply the received input signals to the controller to determine the control of the supplied voltage. The input unit call be a keypad on the heating and cooling apparatus or a wireless receiver, such as a Bluetooth receiver. Likewise, the input unit can include a jack connection permitting a signal source to be connected by a wire connector. Further the controller can include an authentication unit for receiving an authentication code authenticating the received input signals as being from an authorized source.
The controller might provide a uniform voltage signal or a variable voltage signal, and might provide different voltage signals to different ones of the thermoelectric modules.
In another aspect, the present invention is a thermoelectric module made up of a number of semiconductor pellets joined in a series circuit to a voltage source. The semiconductor pellets are positioned between first and second thermal conduction layers. A thermal barrier inhibits heat transfer through the module interior from the heat releasing thermal conduction layer to the heat absorbing thermal conduction layer. The thermal barrier might be provided by a vacuum within the module interior around the semiconductor pellets. Alternatively, the thermal barrier might be provided by a suitable insulating material within the module interior, around the pellets.
In a further aspect, the present invention is a heating and cooling apparatus including first and second thermoelectric modules. A voltage source is connected across the first thermoelectric module, causing temperature changes in the thermal conduction layers of that module. A thermal conductor connects the heated thermal conduction layer panel of the first thermoelectric module with a corresponding thermal conduction layer of the second thermoelectric module so as to heat that layer and create a temperature difference across the second thermoelectric module. This results in a voltage difference across the second thermoelectric module. A voltage sensor is connected across the second thermocectrical module to measure that voltage.